at a rally last night in denver, romney previewed one of his attacks. >> we had 40-straight weeks of unemployment above 8%. and what does the president say to all this? he says forward. i think forewarned a better term. >> reporter: romney's trailing president obama in polls. and his campaign knows the upcoming debates could be their best chance to turn things around. that's why the candidate is practicing. huddled with mock advisers. in the mock debates, senator rob portman is playing barack obama. >> i don't like him very much anymore. >> reporter: as for president obama, he took a break from practice yesterday to visit a campaign office and make a few calls to unsuspecting voters. >> andrea? hi. this is barack obama. how are you? that's right. >> reporter: it was just a brief break for the president, who, like romney, has been rehearsing for days. senator john kerry is playing romney in president obama's practice sessions. the president is out of practice. the last time he debated was four years ago. and, rob and paula, according to the latest abc news/"washington post" poll, 56%